501
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Fonseca C, Domingues MRM, Simões C, Amado F, Domingues P. Reactivity of Tyr-Leu and Leu-Tyr dipeptides: identification of oxidation products by liquid chromatography-tandem mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2009; 44:681-693. [PMID: 19125397 DOI: 10.1002/jms.1543] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The exposure of peptides and proteins to reactive hydroxyl radicals results in covalent modifications of amino acid side-chains and protein backbone. In this study we have investigated the oxidation the isomeric peptides tyrosine-leucine (YL) and leucine-tyrosine (LY), by the hydroxyl radical formed under Fenton reaction (Fe(2+)/H(2)O(2)). Through mass spectrometry (MS), high-performance liquid chromatography (HPLC-MS) and electrospray tandem mass spectrometry (HPLC-MS(n)) measurements, we have identified and characterized the oxidation products of these two dipeptides. This approach allowed observing and identifying a wide variety of oxidation products, including isomeric forms of the oxidized dipeptides. We detected oxidation products with 1, 2, 3 and 4 oxygen atoms for both peptides; however, oxidation products with 5 oxygen atoms were only present in LY. LY dipeptide oxidation leads to more isomers with 1 and 2 oxygen atoms than YL (3 vs 5 and 4 vs 5, respectively). Formation of the peroxy group occurred preferentially in the C-terminal residue. We have also detected oxidation products with double bonds or keto groups, dimers (YL-YL and LY-LY) and other products as a result of cross-linking. Both amino acids in the dipeptides were oxidized although the peptides showed different oxidation products. Also, amino acid residues have shown different oxidation products depending on the relative position on the dipeptide. Results suggest that amino acids in the C-terminal position are more prone to oxidation.
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Affiliation(s)
- Conceição Fonseca
- Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
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502
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Srikanth R, Wilson J, Vachet RW. Correct identification of oxidized histidine residues using electron-transfer dissociation. JOURNAL OF MASS SPECTROMETRY : JMS 2009; 44:755-62. [PMID: 19160434 PMCID: PMC2737336 DOI: 10.1002/jms.1552] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Oxidative modification to the side chain of histidine can noticeably change the collision-induced dissociation (CID) pathways of peptides containing this oxidized residue. In cases where an oxidized peptide consists two or more isomers differing only in the site of modification, oxidation to histidine usually causes the other oxidized sites to be mis-assigned in CID spectra. These spectral misassignments can sometimes be avoided by using multiple stages of MS/MS (MS(n)) or via specially optimized liquid chromatographic separation conditions. In this manuscript, we demonstrate that these misassignments can be more readily and easily avoided by using electron-transfer dissociation (ETD) to dissociate the oxidized peptides. Furthermore, we find that the relative insensitivity of ETD to side-chain chemistry allows the extent of oxidative modification to be determined readily for peptide isomers having more than one site of oxidation. The current results along with previous studies of oxidized peptides suggest that ETD is probably a better technique than CID for obtaining correct sequence and modification information for oxidized peptides.
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Affiliation(s)
- Rapole Srikanth
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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503
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Boys BL, Kuprowski MC, Noël JJ, Konermann L. Protein Oxidative Modifications During Electrospray Ionization: Solution Phase Electrochemistry or Corona Discharge-Induced Radical Attack? Anal Chem 2009; 81:4027-34. [DOI: 10.1021/ac900243p] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Brian L. Boys
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Mark C. Kuprowski
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - James J. Noël
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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504
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Liu S, Zhang C, Xu YF, Yang F, Sun MZ. Electrospray ionization mass spectrometry as a critical tool for revealing new properties of snake venom phospholipase A2. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:1158-1166. [PMID: 19283785 DOI: 10.1002/rcm.3996] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Results from high-performance liquid chromatography/nano-electrospray ionization tandem mass spectrometry (HPLC/nESI-MS/MS) coupled to two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2D SDS-PAGE) indicated that the monomer and dimer of phospholipase A(2) (PLA(2)) coexisted in crude Chinese Agkistrodon blomhoffii Ussurensis snake venom (ABUSV). Then, an acidic PLA(2) with the accurate molecular mass of 13979.6 Da was purified from ABUSV (mo-ABUSV-aPLA(2)). MS/MS-derived peptides from ABUSV-aPLA(2) were compared with other homologous snake venom PLA(2)s, which in turn showed that ABUSV-aPLA(2) is a novel snake venom PLA(2). Meanwhile, the ABUSV-aPLA(2) dimer (di-ABUSV-aPLA(2)) was also obtained. MS/MS analysis identified the same peptides from di-ABUSV-aPLA(2) as from mo-ABUSV-aPLA(2), which indicates that di-ABUSV-aPLA(2) is a homodimer. One Ca(2+) ion is contained per ABUSV-aPLA(2). The Ca(2+) ion is critical for both the hydrolytic activity and the structure of ABUSV-aPLA(2). Pro-Q Emerald and Pro-Q Diamond specific glycoprotein and phosphoprotein staining combined with MS/MS analysis indicated that the ABUSV-aPLA(2) is both a glycoprotein and a phosphoprotein, which to our knowledge is the first such report for a snake venom PLA(2) and thus provides new threads for the study of the functions and structures of snake venom PLA(2)s. One phosphorylation site and the size of the glycan chain are determined by using HPLC/nESI-MS/MS and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS. The delicate utilization of ESI-MS can exert tremendous impact on protein sciences.
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Affiliation(s)
- Shuqing Liu
- Department of Biochemistry & Molecular Biology, Dalian Medical University, Dalian, 116044, China
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505
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Orville AM, Lountos GT, Finnegan S, Gadda G, Prabhakar R. Crystallographic, spectroscopic, and computational analysis of a flavin C4a-oxygen adduct in choline oxidase. Biochemistry 2009; 48:720-8. [PMID: 19133805 DOI: 10.1021/bi801918u] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Flavin C4a-OO(H) and C4a-OH adducts are critical intermediates proposed in many flavoenzyme reaction mechanisms, but they are rarely detected even by rapid transient kinetics methods. We observe a trapped flavin C4a-OH or C4a-OO(H) adduct by single-crystal spectroscopic methods and in the 1.86 A resolution X-ray crystal structure of choline oxidase. The microspectrophotometry results show that the adduct forms rapidly in situ at 100 K upon exposure to X-rays. Density functional theory calculations establish the electronic structures for the flavin C4a-OH and C4a-OO(H) adducts and estimate the stabilization energy of several active site hydrogen bonds deduced from the crystal structure. We propose that the enzyme-bound FAD is reduced in the X-ray beam. The aerobic crystals then form either a C4a-OH or C4a-OO(H) adduct, but an insufficient proton inventory prevents their decay at cryogenic temperatures.
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Affiliation(s)
- Allen M Orville
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973-5000, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
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506
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Paspaltsis I, Berberidou C, Poulios I, Sklaviadis T. Photocatalytic degradation of prions using the photo-Fenton reagent. J Hosp Infect 2009; 71:149-56. [DOI: 10.1016/j.jhin.2008.09.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 09/19/2008] [Indexed: 11/26/2022]
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507
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Zhang Z, Pan H, Chen X. Mass spectrometry for structural characterization of therapeutic antibodies. MASS SPECTROMETRY REVIEWS 2009; 28:147-76. [PMID: 18720354 DOI: 10.1002/mas.20190] [Citation(s) in RCA: 237] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Antibodies, also known as immunoglobulins, have emerged as one of the most promising classes of therapeutics in the biopharmaceutical industry. The need for complete characterization of the quality attributes of these molecules requires sophisticated techniques. Mass spectrometry (MS) has become an essential analytical tool for the structural characterization of therapeutic antibodies, due to its superior resolution over other analytical techniques. It has been widely used in virtually all phases of antibody development. Structural features determined by MS include amino acid sequence, disulfide linkages, carbohydrate structure and profile, and many different post-translational, in-process, and in-storage modifications. In this review, we will discuss various MS-based techniques for the structural characterization of monoclonal antibodies. These techniques are categorized as mass determination of intact antibodies, and as middle-up, bottom-up, top-down, and middle-down structural characterizations. Each of these techniques has its advantages and disadvantages in terms of structural resolution, sequence coverage, sample consumption, and effort required for analyses. The role of MS in glycan structural characterization and profiling will also be discussed.
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Affiliation(s)
- Zhongqi Zhang
- Process and Product Development, Amgen, Thousand Oaks, CA 91320, USA.
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508
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Hamel DJ, Sielaff I, Proudfoot AEI, Handel TM. Chapter 4. Interactions of chemokines with glycosaminoglycans. Methods Enzymol 2009; 461:71-102. [PMID: 19480915 DOI: 10.1016/s0076-6879(09)05404-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Many proteins require interactions with cell surface glycosaminoglycans (GAGs) to exert their biologic activity. The effect of GAG binding on protein function ranges from essential roles in development, organogenesis, cell growth, cell adhesion, inflammation, tumorigenesis, and interactions with pathogens. A classic example is the role of GAGs in the interaction of fibroblast growth factors with their receptors, where GAGs play a role in specificity determination and control of receptor-ligand engagement. The other well-studied example involves the binding of antithrombin to heparin/heparan sulfate, which results in the inactivation of the coagulation cascade. In view of their specialized activity in cellular recruitment, chemokines interact with GAGs, minimally as a mechanism for localization of chemokines to specific anatomical spaces enabling them to act as directional signals for migrating cells. The biological relevance of these interactions has been recently demonstrated by functional characterization of mutants that are deficient in GAG binding. These mutants bind receptor normally in vitro but are unable to recruit cells in vivo. Observations like this have motivated investigations to identify GAG-binding epitopes on chemokines, the specificity and affinity of chemokines for different GAGs, the oligomerization of chemokines on GAGs, and the efficacy of GAG-binding mutants in the context of in vivo cell recruitment and animal models of disease. To this end, several techniques have been developed to measure the interactions of chemokines with GAGs. In this chapter we describe these various assays with particular reference to those that have been used to assess the binding of chemokines to GAGs and to define their epitopes. In the end, we believe both in vitro and in vivo characterization are absolutely necessary for understanding these interactions and their biologic relevance in the context of the whole organism.
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Affiliation(s)
- Damon J Hamel
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, California, USA
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509
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Traoré DAK, El Ghazouani A, Jacquamet L, Borel F, Ferrer JL, Lascoux D, Ravanat JL, Jaquinod M, Blondin G, Caux-Thang C, Duarte V, Latour JM. Structural and functional characterization of 2-oxo-histidine in oxidized PerR protein. Nat Chem Biol 2008; 5:53-9. [PMID: 19079268 DOI: 10.1038/nchembio.133] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 11/17/2008] [Indexed: 11/09/2022]
Abstract
In Bacillus subtilis, PerR is a metal-dependent sensor of hydrogen peroxide. PerR is a dimeric zinc protein with a regulatory site that coordinates either Fe(2+) (PerR-Zn-Fe) or Mn(2+) (PerR-Zn-Mn). Though most of the peroxide sensors use cysteines to detect H(2)O(2), it has been shown that reaction of PerR-Zn-Fe with H(2)O(2) leads to the oxidation of one histidine residue. Oxidation of PerR leads to the incorporation of one oxygen atom into His37 or His91. This study presents the crystal structure of the oxidized PerR protein (PerR-Zn-ox), which clearly shows a 2-oxo-histidine residue in position 37. Formation of 2-oxo-histidine is demonstrated and quantified by HPLC-MS/MS. EPR experiments indicate that PerR-Zn-H37ox retains a significant affinity for the regulatory metal, whereas PerR-Zn-H91ox shows a considerably reduced affinity for the metal ion. In spite of these major differences in terms of metal binding affinity, oxidation of His37 and/or His91 in PerR prevents DNA binding.
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Affiliation(s)
- Daouda A K Traoré
- Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences pour le Vivant, Laboratoire de Chimie et Biologie des Métaux, CEA-Grenoble, 17 avenue des Martyrs, 38054 Grenoble Cedex 9, France
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510
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Stocks BB, Konermann L. Structural Characterization of Short-Lived Protein Unfolding Intermediates by Laser-Induced Oxidative Labeling and Mass Spectrometry. Anal Chem 2008; 81:20-7. [DOI: 10.1021/ac801888h] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bradley B. Stocks
- Departments of Biochemistry and Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Lars Konermann
- Departments of Biochemistry and Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
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511
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Pan Y, Stocks BB, Brown L, Konermann L. Structural Characterization of an Integral Membrane Protein in Its Natural Lipid Environment by Oxidative Methionine Labeling and Mass Spectrometry. Anal Chem 2008; 81:28-35. [DOI: 10.1021/ac8020449] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan Pan
- Departments of Chemistry and Biochemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada, and Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Bradley B. Stocks
- Departments of Chemistry and Biochemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada, and Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Leonid Brown
- Departments of Chemistry and Biochemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada, and Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Lars Konermann
- Departments of Chemistry and Biochemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada, and Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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512
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Mazier S, Villette S, Goffinont S, Renouard S, Maurizot JC, Genest D, Spotheim-Maurizot M. Radiation Damage to a DNA-Binding Protein. Combined Circular Dichroism and Molecular Dynamics Simulation Analysis. Radiat Res 2008; 170:604-12. [DOI: 10.1667/rr1411.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Accepted: 06/18/2008] [Indexed: 11/03/2022]
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513
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Bohon J, Jennings LD, Phillips CM, Licht S, Chance MR. Synchrotron protein footprinting supports substrate translocation by ClpA via ATP-induced movements of the D2 loop. Structure 2008; 16:1157-65. [PMID: 18682217 DOI: 10.1016/j.str.2008.04.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 04/11/2008] [Accepted: 04/15/2008] [Indexed: 11/26/2022]
Abstract
Synchrotron X-ray protein footprinting is used to study structural changes upon formation of the ClpA hexamer. Comparative solvent accessibilities between ClpA monomer and ClpA hexamer samples are in agreement throughout most of the sequence, with calculations based on two previously proposed hexameric models. The data differ substantially from the proposed models in two parts of the structure: the D1 sensor 1 domain and the D2 loop region. The results suggest that these two regions can access alternate conformations in which their solvent protection is greater than that in the structural models based on crystallographic data. In combination with previously reported structural data, the footprinting data provide support for a revised model in which the D2 loop contacts the D1 sensor 1 domain in the ATP-bound form of the complex. These data provide the first direct experimental support for the nucleotide-dependent D2 loop conformational change previously proposed to mediate substrate translocation.
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Affiliation(s)
- Jen Bohon
- Center for Proteomics and Center for Synchrotron Biosciences, Case Western Reserve University, Cleveland, OH 44106, USA
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514
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Jennings LD, Bohon J, Chance MR, Licht S. The ClpP N-terminus coordinates substrate access with protease active site reactivity. Biochemistry 2008; 47:11031-40. [PMID: 18816064 DOI: 10.1021/bi8010169] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Energy-dependent protein degradation machines, such as the Escherichia coli protease ClpAP, require regulated interactions between the ATPase component (ClpA) and the protease component (ClpP) for function. Recent studies indicate that the ClpP N-terminus is essential in these interactions, yet the dynamics of this region remain unclear. Here, we use synchrotron hydroxyl radical footprinting and kinetic studies to characterize functionally important conformational changes of the ClpP N-terminus. Footprinting experiments show that the ClpP N-terminus becomes more solvent-exposed upon interaction with ClpA. In the absence of ClpA, deletion of the ClpP N-terminus increases the initial degradation rate of large peptide substrates 5-15-fold. Unlike ClpAP, ClpPDeltaN exhibits a distinct slow phase of product formation that is eliminated by the addition of hydroxylamine, suggesting that truncation of the N-terminus leads to stabilization of the acyl-enzyme intermediate. These results indicate that (1) the ClpP N-terminus acts as a "gate" controlling substrate access to the active sites, (2) binding of ClpA opens this "gate", allowing substrate entry and formation of the acyl-enzyme intermediate, and (3) closing of the N-terminal "gate" stimulates acyl-enzyme hydrolysis.
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Affiliation(s)
- Laura D Jennings
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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515
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Slysz GW, Percy AJ, Schriemer DC. Restraining Expansion of the Peak Envelope in H/D Exchange-MS and Its Application in Detecting Perturbations of Protein Structure/Dynamics. Anal Chem 2008; 80:7004-11. [DOI: 10.1021/ac800897q] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gordon W. Slysz
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Andrew J. Percy
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - David C. Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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516
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Konermann L, Tong X, Pan Y. Protein structure and dynamics studied by mass spectrometry: H/D exchange, hydroxyl radical labeling, and related approaches. JOURNAL OF MASS SPECTROMETRY : JMS 2008; 43:1021-1036. [PMID: 18523973 DOI: 10.1002/jms.1435] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Mass spectrometry (MS) plays a central role in studies on protein structure and dynamics. This review highlights some of the recent developments in this area, with focus on applications involving the use of electrospray ionization (ESI) MS. Although this technique involves the transformation of analytes into highly nonphysiological species (desolvated gas-phase ions in the vacuum), ESI-MS can provide detailed insights into the solution-phase behavior of proteins. Notably, the ionization process itself occurs in a structurally sensitive manner. An increased degree of solution-phase unfolding is correlated with a higher level of protonation. Also, ESI allows the transfer of intact noncovalent complexes into the gas phase, thereby yielding information on binding partners, stoichiometries, and even affinities. A particular focus of this article is the use of hydrogen/deuterium exchange (HDX) methods and hydroxyl radical (.OH) labeling for monitoring dynamic and structural aspect of solution-phase proteins. Conceptual similarities and differences between the two methods are discussed. We describe a simple method for the computational simulation of protein HDX patterns, a tool that can be helpful for the interpretation of isotope exchange data recorded under mixed EX1/EX2 conditions. Important aspects of .OH labeling include a striking dependence on protein concentration, and the tendency of commonly used solvent additives to act as highly effective radical scavengers. If not properly controlled, both of these factors may lead to experimental artifacts.
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Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada.
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517
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West GM, Tang L, Fitzgerald MC. Thermodynamic Analysis of Protein Stability and Ligand Binding Using a Chemical Modification- and Mass Spectrometry-Based Strategy. Anal Chem 2008; 80:4175-85. [DOI: 10.1021/ac702610a] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Graham M. West
- Department of Chemistry, Duke University, Durham, North Carolina 27708
| | - Liangjie Tang
- Department of Chemistry, Duke University, Durham, North Carolina 27708
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518
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Complementary structural mass spectrometry techniques reveal local dynamics in functionally important regions of a metastable serpin. Structure 2008; 16:38-51. [PMID: 18184582 DOI: 10.1016/j.str.2007.10.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 10/19/2007] [Accepted: 10/27/2007] [Indexed: 01/10/2023]
Abstract
Serpins display a number of highly unusual structural properties along with a unique mechanism of inhibition. Although structures of numerous serpins have been solved by X-ray crystallography, little is known about the dynamics of serpins in their inhibitory active conformation. In this study, two complementary structural mass spectrometry methods, hydroxyl radical-mediated footprinting and hydrogen/deuterium (H/D) exchange, were employed to highlight differences between the static crystal structure and the dynamic conformation of human serpin protein, alpha(1)-antitrypsin (alpha(1)AT). H/D exchange revealed the distribution of flexible and rigid regions of alpha(1)AT, whereas footprinting revealed the dynamic environments of several side chains previously identified as important for the metastability of alpha(1)AT. This work provides insights into the unique structural design of alpha(1)AT and improves our understanding of its unusual inhibition mechanism. Also, we demonstrate that the combination of the two MS techniques provides a more complete picture of protein structure than either technique alone.
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519
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Barelli S, Canellini G, Thadikkaran L, Crettaz D, Quadroni M, Rossier JS, Tissot JD, Lion N. Oxidation of proteins: Basic principles and perspectives for blood proteomics. Proteomics Clin Appl 2008; 2:142-57. [DOI: 10.1002/prca.200780009] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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